In the first place his poem must be deeply conceived, and be unvaryingly self-consistent. Then he must take pains to temper all with variety (varietas), for there is no worse mistake than to glut your hearer before you are done with him. What then are the dishes which would create distaste rather than pleasure? The third poetic quality is found in but few writers, and is what I would term vividness (efficacia);….By vividness I mean a certain potency and force in thought and language which compels one to be a willing listener. The fourth is winsomeness (suavitas), which tempers the ardency of this last quality, of itself inclined to be harsh. Insight and foresight (prudentia), variety, vividness, and winsomeness, these, then, are the supreme poetic qualities.
—Giulio Cesare Scaligero (1484-1558), “The Four Attributes of the Poet,” Select Translations from Scaliger's Poetics (H. Holt, 1905), translated Frederick Morgan Padelford